'Plesiosauria' definitions:
Definition of 'Plesiosauria'
From: WordNet
noun
Any of the plesiosaurs [syn: Plesiosauria, suborder Plesiosauria]
Definition of 'Plesiosauria'
From: GCIDE
- Plesiosauria \Ple`si*o*sau"ri*a\, n. pl. [NL. See Plesiosaurus.] (Paleon.) An extinct order of Mesozoic marine reptiles including the genera Plesiosaurus, and allied forms; -- called also {Sauropterygia}. [1913 Webster]